# Special 24

The number $24$ is special because it is just one short of being a square number.

So $24 + 1 = 25$ and $5^2 = 25$

AND when you double $24$ the answer is also one short of being a square

number.

So $24 \times 2 = 48$ and $48 + 1 = 49$ and $7^2 = 49$.

Find another number that is special in the same way as $24$.

This one is tough! **Susannah** from Headington Junior School
has given it a try...

"The closest I can get is 8 times 8 which is 64, - 1 = 63.

63 + 63 = 126, 121 is 11 squared.

8.5 times 8.5 = 72.25, rounded up to 73.

72 + 72 = 144 which is 12 squared".

**Sara from E**ast
Bergholt VC Primary, Suffolk

"At first I thought it was hard, but in the end it was easy!

840 + 1 = 841

841 = 29 x 29

840 x 2 = 1680

1680 + 1 = 1681

1681 = 41 x 41

So the Special Number is 840."